Apparatus for coating shaped can ends



July 14, 1936.-

A. L. KRONQUEST APPARATUS FOR COATING SHAPED CAN ENDS Filed Aug. 6, 19542 Sheets-Sheet 1 July 14, 1936. A. L. KRONQUEST.

APPARATUS FOR COATING SHAPED CAN ENDS Filed Aug. 6, 1954 2 Sheets-Sheet2 Patented July 14, 1936 UNITED STATES PATENT OFFICE it Arman-res rzrzsitrmc snarnn' Alfred L. Kronquest, Syracuse, N. Y., assignor to C t t0m Co pany, Inc.. New York, 4 N. Y., a corporation of New YorkApplication August 8, 1934, Serial no. 138,149 I Claims. (01. 91-42) Theinvention relates to new and useful improvements in an apparatus forapplying a protective enamel to a can end which has been shaped readyfor attachment to the can body. In my prior Patent No. 2,046,197,granted June 30, 1936, there is disclosed a method of applying aprotective enamel to a can end which includes the dipping of the face ofthe can end which is tobe coated in a bath of enamel, and then rotatingthe end rapidly after it is removed from the bath for distributing thecoating uniformly over the surface of the end and discharging thesurplus enamel from the end by centrifugal. force. The can end which iscoated by the method of my prior patent is of the commercial form. for

closing an open top can. The present invention has to do with anapparatus for coating a can end which is cone-shaped and terminates in aneck which may be closed by an ordinary crown seal. Considerabledifilculty has been experienced in applying a uniform coating of enamelthroughout the entire extent of such a shaped can end, as the neckportion is so shaped as to form pockets which trap the enamel andprevent an even distribution of the coating through the action ofcentrifugal force thereon.

An object of'tiiepresent invention is to provide an apparatus which isequipped with means for projecting astream of air against the freshlycoated surface duringthe rotating thereof and in the regions where thecoating is likely to be trapped so as to. force the coating from thetrap and to causethe coating to be evenly distributed throughout theentire inner surface of the end.

A further object of the invention is to provide an apparatus of theabove type wherein the air blast is automatically controlled by theshifting of the end to a position free from the bath for the rotating ofthe same.

A still further object of the invention is to provide means forpreventing the rotation of the chuck when disconnected from its rotatingmeans and during the connecting of the end to the chuck and thedisconnecting of the end therefrom.

These and other objects will in part be obvious and will in part behereinafter more fully disclosed. i

In the drawings-- Figure 1 is a view partly in side elevation and partlyin section showing an apparatus embodying the improvements;

Fig. 2 is an enlarged view showing the can end with the coating appliedthereto and positioned for rotation for distributing the coating evenlyover the inner surface of the can end;

Fig. 3 is a detail view showing a portion of the neck of the can endwith the coating trapped in the pocket formed by the bead at the mouthof the neck of the can end and prior to subjecting the same tothe airblast, and

Fig. 4 is a similar view showing the thinning of the coating by the airblast as the end is rotated.

The invention as above noted is particularly adapted for the coating ofa can end which is cone-shaped and drawn so as to provide an integralneck beaded at its open end for the attachment of a crown seal closureor some other similar closure. The can end as shown in the drawingsincludes a cone-shaped portion 1, a channel portion 2 which is of theusual construction for forming a double .seam with the can body, and aneck portion 34 The neck portion 3 is provided with a bead 4' at itsupper end which extends 15 from an opening 5 to ,the shoulder 6. This isfor the purpose of providing the shoulder underneath which theprojections on the crown seal closure engage for the sealing of thecontainer. It is desired to provide the surface of this end with a 0protective enamel. It will be-impracticable to coat the metal in thesheet before the end is formed, as the strain incident to the drawing ofthe metal for forming the shape of the end just referred to is likely tobreak the enamel at points so that certain products placed in thecontainer which'would not attack the enamel will re-act upon the exposedmetal either to damage the metal, causing pinholing thereof, or toinjure the contents of the can, as for example, if the can is used forthe packaging of beer. It is well known that if beer contacts with metalit becomes clouded, and therefore, the surface of the metal must becompletely covered by the enamel. Applicants problem resided in theapplying of a protective enamel to the entire inner surface of the canend when shaped as described above. The problem was solved by theapplying of the enamel coating to the can and preferably by di ping thesame in a bath of enamel, and then rotating the end rapidly for thepurpose of distributing the enamel in a thin layer over the surface ofthe end and the discharging of the surplus enamel from the end bycentrifugal force. There were still pockets in the region of the neckwhich trapped the enamel and prevented centrifugal force acting thereonfrom causing it to flow, leaving a thick coating. This was overcome bythe application ofa gentle blast of air in the region where the enamelis trapped so as to force it from the trap and permit the centrifugalforce is carried by a shaft I mounted in suitable hearings in the frameand attached to the shaft is a handle l5. By rotating the shaft throughthe aid of the handle, the sleeve Il may be raised and lowered in thesupporting frame. Extending through the sleeve is a shaft l6 which ishollow. Said shaft is mounted for rotation in bushings I1, I! carried bythe sleeve I l. to the upper end of this hollow shaft I6 is a conefriction gear 18. Said cone friction gear I 8, when the sleeve II israised, is brought into contact with the cone friction gear i9 mountedon the outer end of a shaft 20 of a motor M which is mounted on thesupporting frame I. The motor rotates continuously, and when the sleeveH is raised so as to bring the friction gear l8 into contact with the.friction gear I 9, then the shaft 16 will be rotated, and rotated veryrapidly. The motor is preferably of a type that will impart a speed ofbetween three and four thousand revolutions per minute to the shaft 16.Fixed to the lower end of the shaft I6 is a chuck 21. said chuck 2! isprovided with a series of spring arms 22, 22. These spring arms are bentoutwardly and curved at 23 so as to conform to the outer surface of thebead 4 at the neck of the can end. The lower ends of these spring armsare bent outwardly as indicated at 24. The can end is placed againstthese outwardly tapered extending ends 24 .and forced into the curvedportions which conform to the head 4 and. will be firmly gripped bythese spring arms and thus held attached to the chuck. After the end isattached to the chuck, then the lever 15 is turned in acounter-clockwise direction so as to lower the shaft and completelyimmerse the can end in thebath of enamel. After the end has beencompletely immersed, it is lifted from the bath with a coating of enameladhering to the inner and outer surfaces thereof. As soon as thefriction gear l8 contacts with the friction gear l9, then the shaft willbe rotated rapidly, and this will rotate the end very rapidly.Centrifugal force acting on the coating will cause the coating to flowtoward the extreme periphcry of the can end. There will be left,however, a thin film of adhering coating over the entire surface of theend, both on the inner and outer faces thereof. The surplus coating willbe discharged from the periphery of the end.

During the rotation of the end, the recess formed on the inner face ofthe head 4 serves to trap theenamel so that the centrifugal force cannotalone move the enamel from the recess. This is due to the fact thatportions of the inner surface of this beaded portion are necessarily ofgreater diameter than portions of the neck therebelow.

, Extending down through the shaft I6 is a pipe 25. Said pipe 25 isprovided with a distributing head 26 on the lower end thereof, and saiddistributing head is formed with a series of openings 21. This pipe 25is connected to a valve housing 28 which is attached to a pipe line 29leading to a suitable source of air supply. The

.pipe 25 is so disposed that when the sleeve I6 is raised to bring thefriction gears into contact, that the head 26 is moved down through theopening in the end so that air blasts coming from the openings 21 willcontact with the enamel in the trap formed by this inner curved surfaceat the beaded neck. The air blast is gentle so as not to strip theenamel completely from this surface, but it will cause the enamel toflow from the recess or trap to a point where Fixed it will be taken upby centrifugal force and carried along by the flowing enamel so that itwill be distributed and the surplus discharged. The

blast of air may be so regulated that the coating of enamel throughoutthe entire inner surface of the end will be substantially of uniformthickness, and the entire metal surface completely covered by theenamel.

In order to regulate the flow of air from the nozzle, there is an arm 30attached to the shaft time when the end begins its rotation, and will 20continue while the end is being rotated.

The arm I0 is provided with a bracket 33 in which is mounted a brakemember 34. Said brake member has a reduced shank 35 surrounding which isa spring 36. The spring bears 25 against the head of the brake member,and also against an abutment 31. The purpose of the spring is to holdthe brake member projecting from the bracket as indicated in Fig. 1.Said brake member is provided with a tapered face 38 at its upper sideand the tapered face 39 at its lower side. This brake member isso posi-'tioned that when the shaft is lowered from the position shown in Fig. 1,sufliciently to disconnect the gear II from the gear IS, the gear illwill as contact with the brake member and stop its rotation. This is theproper positioning of the shaft for the attaching of the end to thechuck. While said gear II is resting against the brake member, the endis placed on the chuck, and then the shaft is lowered, and as it islowered it is forced by the brake member. On the upward movement of theshaft, the gear will pass the brake member and be freed therefrom sothat it may be rotated.

From the above it will be apparent that an apparatus has been providedin which a can end may be chucked for rotation, after which the end maybe lowered and immersed in a bath of enamel. The end may then be raisedand connected to a rotating means whereby it will be rapidly rotated. Atthe same time, the inner surface of the end throughout any regions whichmay 'pocket the enamel are subjected to a gentle blast of air for thepurpose of dislodging the enamel from the trap so that the centrifugalforce, together with the air blast, will bring about an evendistribution of the enamel throughout the entire surface of the can end,thus producing a very thin film completely covering the surface of themetal. After the end is coated, it is dried and may be baked in order toset or harden the enamel.

The method employed in the coating of the can end by the apparatusdescribed above forms 7 and the surplus discharged, leaving a moreuniform coating, and insuring that the entire surface, of the metal willbe coated, particularly in I the inner face thereof, so that no productwithin the container can contact with the metal of the end.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent, is-

1. An apparatus for applying a protective enamel to the inner face of aformed can end comprising a supporting frame, a tank carried therebyhaving a bath of enamel therein, a projecting arm overhanging said bath,a chuck to which the end may be attached, a support for said chuck,means for moving said support vertically for immersing the end in thebath, means for rotating said support, and means for directing a blastof air against thecoated surface, where desired, during the rotationthereof for aiding in the forming of a coating of norm thickness.

2. An apparatus for applying a protective enamel to the inner. face of aformed can end comprising a supporting frame, a tank carried therebyhaving a bath of enamel therein, a projecting arm overhanging said bath,a chuck to which the end may be attached, a support for said chuck,means for moving said support vertically for immersing the end in thebath, means for rotating said support including friction gearscontacting with each other only when said chuck is raised to its extremeelevated position, and a yielding brake adapted to prevent the rotationof said support when the gears are out of contact and while the ends arebeing attached to and removed from the chuck and while the end is beingimmersed in the enamel bath.

3. An apparatus for applying a protective enamel to the inner face of aformed can end comprising a supporting frame, a tank carried therebyhaving a bath of enamel therein, a projecting arm overhanging said bath,a chuck to which the end may be attached, a support for said chuck,means for moving said support vertically for immersing the end in thebath, means for rotating saidsupport including friction gears contactingwith each other only when said chuck is raised to its extreme elevatedposition, and means for directing a blast of air against the coatedsurface, where desired, during the rotation thereof for aiding in theforming of a coating of uniform thickness.

4. An apparatus for applying a protective enamel to the inner face of aformed can end comprising a supporting frame, a tank carried therebyhaving a bath of enamel therein, a projecting arm overhanging said bath,a. chuck to which the end may be attached, a hollow shaft to which saidchuck is attached, a sleeve in which said shaft is mounted for rotation,means for raising and lowering the sleeve for causing the can endcarried by the chuck to be immersed in the bath and removed therefrom, afriction gear attached to said shaft, a motor-driven friction gearcarried by the frame and positioned so that when said sleeve is inelevated position, said gears will contact and the shaft will berotated, and a pipe extending through said hollow shaft and having ahead at the lower end thereof provided with openings through which airjets may be directed 'said shaft is mounted for rotation,

against the inner surface of the can'cnd at the region's desired andduring the rotation thereof.

5. An apparatus for applying a protective enamel to the inner face of aformed can end comprising a, supporting frame, a tank carried 5 therebyhaving a bath of enamel therein, a pro- :lecting arm overhanging saidbath, a chuck to which the end may be attached, a hollow shaft to whichsaid chuck is attached, a sleeve in which said shaft is mounted forrotation, means for raising and lowering the sleeve for causing the canend carried by the chuck to be immersed in the bath and removedtherefrom, a friction gear attached to said shaft, a motor-drivenfriction gear carried by the frame and positioned so that when saidsleeve is in elevated position, said gears will contact and the shaftwill be rotated, a pipe extending through said hollow shaft and having ahead at the lower end thereof provided with openings through which airjets may be directed against the inner surface of the can end at theregions desired and during the rotation thereof,

a valve in said air pipe, and devices controlled by the movement of thesleeve so that said valve is opened for discharging air against thesurface of the can end only during the time when saidend is to berotated.

6. An apparatus for applying a protective enamel to the inner face of aformed can end comprising a supporting frame, a tank carried therebyhaving a bath of enamel therein, a projecting arm overhanging said bath,a chuck to which the end may be attached, a hollow shaft to which saidchuck is secured, a sleeve on which said shaft is mounted for rotation,said sleeve having a rack on one side thereof, a pinion engaging saidrack, a shaft carrying the pinion, means for rotating said pinion shaftfor raising and lowering the sleeve, a friction gear carried at theupper end of said hollow shaft, a motor-driven -40 friction gear mountedon the frame and adapted to contact with the gear on the hollow shaftwhen the sleeve is elevated for the rotating of the chuck and thecontainer end carried thereby.

7. An apparatus for applying a protective enamel to the inner face of aformed can end comprising a supporting frame, a tank carried therebyhaving a bath of enamel therein, a projecting arm overhanging said bath,a chuck towhich the end may be attached, a hollow shaft to 80 which saidchuck is secured, asleeve on which said sleeve having a rack on one sidethereof, a pinion engaging said rack, a. shaft carrying the pinion,means for rotating said pinion shaft for raising and lowering thesleeve, a friction gear carried at the upper end of said hollow shaft, amotor-driven friction gear mounted on the frame and adapted to contactwith the gear on the hollow shaft when the sleeve is elevated for therotating of the chuck and the container end carried thereby, and a pipeextending through said hollow shaft and having a head at the lower endprovided with openings through which jets of air may issue, said pipebeing disposed so that when 55 the sleeve is raised and the gearsconnected for rotation, the head of said pipe will extend through theopening in the can end and cause the air jets to engage the innersurface of the can end.

ALFRED L. KRONQUEST.

